Reformate scheduler controller #777
Handle missing scheduler controllers gracefully #777
Reset $run in the scheduler loop. Check if the method check method exists.
Integrate the gradual upgraded into the scheduler service.
Don't return after gradual upgrade call.
Add config option to enable the profiler everywhere

* Render profiler output in scheduler
* Disable profiler in /json controller

Conflicts:

	application/controllers/scheduler.php
Scheduler: Check and increase max_execution_time if its too low

Related to #928
Scheduler: Add locking mechanism base on using mysql

Prevent multiple schedulers running at once. We create a fake
locking mechanism based on setting a flag in the settings table.

Related to #928
Optimize cleanup scheduler to only load image media type
Merge pull request #75 from rjmackay/scheduler-locking

Scheduler Improvements